Self-propelled surface cleaning machine and method for operating a self-propelled surface cleaning machine

ABSTRACT

Provided is a self-propelled surface cleaning machine including a front wheel device, a steering device associated therewith, a steering angle sensor device capable of detecting a steering angle at the front wheel device, a rear wheel device having a left rear wheel and a right rear wheel, an electromotive drive device associated with each of the left rear wheel and the right rear wheel, a cleaning liquid application device by which cleaning liquid is applicable to a floor/ground in an application area arranged between the front wheel device and the rear wheel device, and a control device operatively connected for signal communication with the steering angle sensor device and the electromotive drive devices, wherein each electromotive drive device is controllable individually depending on signals from the steering angle sensor device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of international application numberPCT/EP2011/059681, filed on Jun. 10, 2011, which is incorporated hereinby reference in its entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a self-propelled surface cleaning machine.

The invention further relates to a method for operating a self-propelledsurface cleaning machine comprising a steered front wheel device and adriven rear wheel device.

DE 10 2004 022 359 A1 discloses a mobile surface cleaning machinecomprising a drive unit for propelling the surface cleaning machine andcomprising at least one cleaning tool, wherein the at least one cleaningtool and/or the drive unit has a plurality of operating modes andwherein a particular mode of operation is selectable by the user by wayof operator controls.

EP 1 239 762 B1 discloses a movable carriage, in particular a workingmachine or surface cleaning machine, comprising at least one pivotablewheel and/or a pivotable actuating, working or cleaning unit and atleast one sensor device. The sensor device is arranged such that it is,at least relatively, co-pivotable with the at least one steerable wheeland/or the pivotable actuating, working or cleaning unit in the samepivoting direction.

DE 30 43 004 C2 discloses an electric single wheel drive.

DE 694 02 303 T2 discloses an electric drive assembly comprising anelectric differential drive axis.

U.S. Pat. No. 5,487,738 discloses a drive system for an electricvehicle.

SUMMARY OF THE INVENTION

In accordance with the invention a self-propelled surface cleaningmachine having a high level of driving safety is provided.

In accordance with an embodiment of the invention, the self-propelledsurface cleaning machine comprises:

-   -   a front wheel device;    -   a steering device associated with the front wheel device;    -   a steering angle sensor device by which a steering angle at the        front wheel device is capable of being detected;    -   a rear wheel device having at least one left rear wheel and at        least one right rear wheel;    -   a first electromotive drive device associated with the at least        one left rear wheel;    -   a second electromotive drive device associated with the at least        one right rear wheel;    -   a cleaning liquid application device by which cleaning liquid is        capable of being applied to a floor/ground in an application        area that is arranged between the front wheel device and the        rear wheel device; and    -   a control device operatively connected for signal communication        with the steering angle sensor device, the first electromotive        drive device and the second electromotive drive device, wherein        each of the first electromotive drive device and the second        electromotive drive device is capable of being controlled        individually depending on signals from the steering angle sensor        device.

In accordance with an embodiment of the invention, increased drivingsafety is reached, particularly also when travelling on wet floor/groundand when running uphill. Arranging the application area between thefront wheel device and the rear wheel device results in a high level ofcleaning efficiency, while ensuring that in forward travel (in adirection of the velocity vector from the rear wheel device to the frontwheel device), the steered front wheel device runs in a non-applicationarea (“dry area”). The driven rear wheel device then runs in anapplication area (“wet area”). The traction that is obtained in said“wet area” may in principle be worse compared to that obtained in thearea in which the front wheel device is run; this is particularly truewhere the cleaning liquid contains chemical additives such as soft soapwhich increase the slipperiness of the floor/ground.

In the solution in accordance with the invention, the firstelectromotive drive device and the second electromotive drive device arecontrolled individually, i.e., independently of each other, whenrequired. The result is that optimized adaptation to the groundconditions is obtained even in cornering. Traction can be increased.This in turn allows for an optimized speed to be adjusted, adapted tothe ground conditions. This results in time-effective cleaning with highdriving safety.

By controlling the first electromotive drive device and the secondelectromotive drive device individually in cornering and in particularby adjusting different rotational speeds in cornering, it is possible toensure an optimized work result.

The control device comprises in particular an electronic differentialdevice for the at least left rear wheel and the at least one right rearwheel. An optimized adjustment, adapted to the existing groundconditions, can thereby be obtained in cornering, in order to achieveenhanced driving safety with optimized speed.

In an embodiment, provision is made for the first electromotive drivedevice and/or the second electromotive drive device to comprise atransverse flux motor. With use of such a motor as a single wheel drive,it is possible to implement high efficiency with a wide torque range.

In an embodiment of advantageous design, the front wheel devicecomprises one or more steering rollers. A (non-driven) steering rollerprovides for stable tracking. Steering can be implemented in a simplemanner.

It is advantageous for the control device to comprise a speed limitingdevice, wherein a maximum speed is dependent on the steering angle.Increased driving safety can thereby be achieved. Furthermore, by makinguse of an in particular predetermined maximum speed, time-effectivecleaning of a floor/ground area can be achieved.

Control parameters of the control device for the first electromotivedrive device and the second electromotive drive device may compriserotational speed and direction of rotation. By way of example, whenturning a narrow corner (for example a turn through a steering angle of90°), it may be advantageous for the inside rear wheel to be adjusted soas to rotate in a direction counter to that of the outside rear wheel.

It is further advantageous for the rear wheel device to have a sensordevice associated with it, said sensor device sensing wheel parametersand in particular slip-determined wheel parameters, and for the sensordevice to be operatively connected for signal communication with thecontrol device. It is thereby possible to perform anti-slip control whencorresponding slip-determined parameters are sensed.

In this connection, it is advantageous for the control device tocomprise an anti-slip control.

In particular, one or more nozzles for cleaning liquid are provided,said nozzles being arranged between the front wheel device and the rearwheel device. An application area can thereby be formed which isarranged between the front wheel device and the rear wheel device. Byway of the nozzles, water or a water/additive mixture can be applied,for example.

In particular, in forward travel, applying cleaning liquid to thefloor/ground to be cleaned is effected behind the front wheel device andin front of the rear wheel device. This allows steering on the frontwheel device to be performed in a non-application area (“dry area”).Drive is effected in the application area.

It is further advantageous for one or more scrubbing elements to beprovided, said scrubbing elements being arranged in particular betweenthe front wheel device and the rear wheel device. Effective cleaning canthereby be achieved. Cleaning liquid from a nozzle can be applieddirectly to the scrubbing element(s) and/or it can be sprayed directlyonto a floor/ground surface.

For example, a surface cleaning machine is configured as a scrubbingmachine and in particular as a scrubber vacuum machine. A scrubbervacuum machine sucks up excess cleaning liquid after scrubbing.

It is in principle possible for a self-propelled surface cleaningmachine constructed in accordance with the invention to beattendant-controlled, for example by a driver. It is also possible forthe self-propelled surface cleaning machine to be remote controlled orto be configured as a cleaning robot.

Further provided in accordance with the invention is a self-propelledsurface cleaning machine, in particular sweeping machine, comprising afront wheel device, a steering device associated with the front wheeldevice, a steering angle sensor device by which a steering angle at thefront wheel device is capable of being detected, a rear wheel devicehaving at least one left rear wheel and at least one right rear wheel, afirst electromotive drive device associated with the at least one leftrear wheel, a second electromotive drive device associated with the atleast one right rear wheel, and a control device operatively connectedfor signal communication with the steering angle sensor device, thefirst electromotive drive device and the second electromotive drivedevice, wherein each of the first electromotive drive device and thesecond electromotive drive device can be controlled individuallydepending on signals from the steering angle sensor device.

In such a self-propelled surface cleaning machine, in particular when itis configured as a sweeping machine, no provision is made for applyingcleaning liquid between the front wheel device and the rear wheeldevice. Such a self-propelled surface cleaning machine can be operatedwith increased driving safety. For example when driving over wet leaves,optimized operation can be implemented by the individually independentcontrol of the first electromotive drive device and the secondelectromotive drive device.

In accordance with an embodiment of the invention, a method foroperating a self-propelled surface cleaning machine having a steeredfront wheel device and a driven rear wheel device is provided, wherein afloor/ground to be cleaned has cleaning liquid applied thereto and anapplication area is located between the front wheel device and the rearwheel device, said method achieving optimized driving safety.

In accordance with an embodiment of the invention, a first drive deviceassociated with a left rear wheel and a second drive device associatedwith a right rear wheel is controlled individually depending on asteering angle at the front wheel device.

The method in accordance with the invention has the advantages that havealready been explained in connection with the description of the surfacecleaning machine constructed in accordance with the invention.

Further advantageous embodiments have likewise already been described inconnection with the description of the surface cleaning machineconstructed in accordance with the invention.

In the method in accordance with the invention, steering on the frontwheel device is effected outside of the application area, i.e., in a“dry area”. Drive of the rear wheel device is effected in an applicationarea, i.e., in a “wet area”. By the independent and individual controlcapability of the first drive device and the second drive device andhence the independent control of the left rear wheel and the right rearwheel, optimized traction, adapted to the ground, can be achieved,particularly also in cornering.

In accordance with an embodiment of the invention, there is provided amethod for operating a self-propelled surface cleaning machine, and inparticular for operating a self-propelled sweeping machine, having asteered front wheel device and a driven rear wheel device, said methodachieving optimized driving safety.

In accordance with an embodiment of the invention, a first drive deviceassociated with a left rear wheel and a second drive device associatedwith a right rear wheel are controlled individually depending on asteering angle at the front wheel device.

The method in accordance with the invention has the advantages that havealready been explained in connection with the description of the surfacecleaning machine, in particular sweeping machine, constructed inaccordance with the invention.

In particular, the rear wheel device is electromotively driven, with anelectronic differential device being used for the first drive device andthe second drive device. By way of the first drive device and the seconddrive device, wheel motors are provided that are capable of beingcontrolled independently of each other, wherein differential control iscapable of being performed, adapted to the respective steering angle andalso adapted to the ground.

In particular, the first drive device and the second drive device arecontrolled in respect of rotational speed and direction of rotation. Itmay also be advantageous for a maximum speed to be predetermined, saidmaximum speed depending on the steering angle.

The following description of preferred embodiments serves to explain theinvention in greater detail in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a first exemplary embodiment ofa surface cleaning machine constructed in accordance with the invention;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1; and

FIG. 3 is a schematic side view of a second exemplary embodiment of asurface cleaning machine.

DETAILED DESCRIPTION OF THE INVENTION

A first exemplary embodiment of a self-propelled surface cleaningmachine constructed in accordance with the invention, shown in FIGS. 1and 2 and designated at 10, is attendant-controlled. The surfacecleaning machine 10 has a body 12. Mounted to the body 12 are a frontwheel device 14 and a rear wheel device 16. Via the front wheel device14 and the rear wheel device 16, the surface cleaning machine 10 candrive on a floor/ground 18 that is to be cleaned.

In an exemplary embodiment, the front wheel device 14 comprises asteering roller 20. The steering roller 20 is connected to a steeringdevice generally designated at 22. By way of the steering device 22, anangular position (indicated by reference numeral 24 in FIG. 2) of thesteering roller 20 relative to a central axis 26 of the surface cleaningmachine 10 can be adjusted. In straight ahead travel (indicated by thereference numeral 27 in FIGS. 1 and 2), the steering roller 20 isoriented parallel to the central axis 26 and a corresponding steeringangle is a zero angle.

The steering device 22 defines a steering axis 28. Said steering axis 28preferably intersects the central axis 26. The steering axis 28 isoriented transversely and for example perpendicularly to the centralaxis 26.

Arranged on the body 12 is a seat 30 for a driver. A driver sitting onthe seat 30 can operate a steering wheel 32 of the steering device 22.

The surface cleaning machine 10 comprises a steering angle sensor device34. By way of said sensor device, a steering angle at the front wheeldevice 14 (in particular an angular position of the steering roller 20relative to the central axis 26) is capable of being detected.

The steering device comprises for example a mechanical steering rodwhich connects the steering roller 20 and the steering wheel 32. Inparticular, the steering angle sensor device 34 then detects an angularposition of the steering wheel 32 or the steering rod.

Alternatively, it is for example also possible for the steering device22 to comprise steering rods with a gear interposed therebetween. Onesteering rod is connected to the steering wheel 32 and another steeringrod is connected to the steering roller 20. A gear interposedtherebetween provides for rotational angle reduction or rotational angleincrease. The gear can also be connected to the steering wheel 32directly or connected to the steering roller 20 directly.

It is for example also possible for the steering device 22 to comprise asteering motor; a steering position of the steering roller 20 is thencontrolled by motor.

The steering roller 20 is capable of being rotated about a rotation axis36 transverse to the central axis 26. In straight ahead travel in thestraight ahead travel direction 27, the rotation axis 36 is orientedperpendicularly to the central axis 26.

The rear wheel device 16 comprises (at least) one left rear wheel 38 and(at least) one right rear wheel 40 (with respect to straight aheadtravel) (FIG. 2). The left rear wheel 38 is fitted on a shaft 42 a. Theright rear wheel is fitted on a shaft 42 b. The shafts 42 a and 42 bhave coaxial axes of rotation 44 transverse and in particularperpendicular to the central axis 26. The rear wheels 38 and 40 areunsteered, i.e., their axes of rotation 44 are fixed relative to thecentral axis 26.

The left rear wheel 38 has a first electromotive drive device 46associated with it. Said first electromotive drive device 46 comprises awheel motor which drives the left rear wheel 38 directly.

The first electromotive drive device 46 comprises for example atransverse flux motor.

The right rear wheel 40 has a second electromotive drive device 48associated with it. This likewise comprises a wheel motor, said wheelmotor driving the right rear wheel 40 directly.

The second electromotive drive device 48 likewise preferably comprises atransverse flux motor.

The surface cleaning machine 10 comprises a control device 50. Thesteering angle sensor device 34 is operatively connected for signalcommunication with said control device 50; it sends its signals(detected steering angles) to the control device 50 for furtherprocessing.

The surface cleaning machine 10 comprises corresponding actuating pedals52 for a driver, in particular an “accelerator pedal” and a “brakepedal”. Actuating the “accelerator pedal” allows the speed to beincreased, while actuating the “brake pedal” effects deceleration. Thecorresponding pedals are operatively connected for signal communication(indicated by reference numeral 54 in FIG. 2) with the control device50. A corresponding position of these pedals causes the firstelectromotive drive device 46 and the second electromotive drive device48 to be correspondingly controlled via the control device 50. To thisend, these are operatively connected for signal communication with thecontrol device 50; this is denoted by reference numerals 56 a and 56 bin FIG. 2. The control device 50 provides corresponding control signalsto the first electromotive drive device 46 and the second electromotivedrive device 48. In particular, the corresponding control signals causeadjustment of the rotational speed and also of the direction of rotationat each of the left rear wheel 38 and the right rear wheel 40. Brakepedal application effects deceleration, and a corresponding brake isactuated.

The rear wheel device 16 has associated with it a sensor device that isgenerally designated at 58 and senses wheel parameters, in particularwheel parameters characteristic of slip. To this end, the sensor device58 comprises a first part 60 a which is associated with the left rearwheel 38 and a second part 60 b which is associated with the right rearwheel 40. By way of example, the sensor device 58 is used to determinethe actual rotational speeds of the left rear wheel 38 and the rightrear wheel 40. By comparing these values to the rotational speedspredetermined for the electromotive drive devices 46, 48 by the controldevice 50, it is then possible to determine whether or not a slipcondition is present.

The sensor device 58 is operatively connected for signal communicationwith the control device 50. Corresponding sensor signals are transmittedthereto for further processing.

The surface cleaning machine 10 is configured as a scrubbing machine andin particular as a scrubber vacuum machine. It comprises one or morescrubbing elements 62, in particular scrubbing discs. These are arrangedon an underside 64 of the surface cleaning machine 10, facing thefloor/ground 18. A scrubbing element 62 is mounted, for examplerotatably mounted, between the rear wheel device 16 and the front wheeldevice 14.

The surface cleaning machine 10 comprises an application device 66 forcleaning liquid via which a cleaning liquid, in particular a mixture ofwater and added chemical, is capable of being applied in an applicationarea 68 to the floor/ground 18 to be cleaned.

To this end, the application device 66 comprises in particular aplurality of nozzles 70 via which the cleaning liquid is capable ofbeing applied to the application area 68.

The nozzles 70 can be arranged in one or more rows.

The nozzles 70 can be arranged and configured such that the cleaningliquid is sprayed directly onto the scrubbing element(s) 62 (tool(s)),from where it gets to the floor/ground, and/or such that it is sprayeddirectly onto the floor/ground 18.

The application area 68 is between the front wheel device 14 and therear wheel device 16. This means that when operating in cleaning travel,the front wheel device 14 travels in an area that has no cleaning liquidapplied thereto (“dry area”), while the rear wheel device 16 travels inan area of the floor/ground 18 that does have cleaning liquid appliedthereto, i.e., in the “wet area” (where chemical additives may bepresent).

The control device 50 comprises an electronic differential device 72. Byway of the electronic differential device 72, the corresponding drivedevices 46, 48 for the left rear wheel 38 and the right rear wheel 40can be controlled differently from each other if required. Inparticular, control is effected individually depending on the steeringangle detected by the sensor device 34. For example, when turning acorner, the left rear wheel 38 or the right rear wheel 40 is made totravel faster than the other one, depending on the steering position atthe front wheel device 14.

When turning the steering wheel through a large angle (for example aturn with a 90° steering angle), the left rear wheel 38 and the rightrear wheel 40 may even be made to rotate in opposite senses.

The first electromotive drive device 46 and the second electromotivedrive device 48 are controlled individually, i.e., independently of eachother, via the differential device 72 of the control device 50. Inprinciple, the front wheel device 14 is tracking.

High cornering speeds can thereby be achieved. Furthermore, increaseddriving safety on wet floor/ground can be achieved (it is the drivenrear wheel device 16 that moves in the “wet area”). Increased drivingsafety in uphill driving is also provided. Steering is effected in the“dry area”, and control of the rear wheel device 16 is effected in the“wet area”. Cleaning liquid is applied behind the front wheel device 14and in front of the rear wheel device 16.

Anti-slip control can be implemented via the sensor device 58. To thisend, the control device 50 comprises an anti-slip control 74. This isused to determine from signals of the sensor device 58 whether or not aslip condition is present. In particular, if slip is present, therotational speed may be increased by corresponding control of the drivedevices 46, 48.

The control device 50 further comprises a speed limiting device 76. Theanti-slip control 74 may be part of the speed limiting device 76. Thespeed limiting device 76 limits the speed to a predetermined value,depending on the steering angle, and this can be accomplished,particularly in cornering, by differential control of the electromotivedrive devices 46 and 48.

Integrated in the surface cleaning machine 10 is a tank 78 for cleaningliquid. Provision may be made for the tank 78 to comprise a portion forholding for example water and a portion for holding chemical additives.Via the tank 78 or a mixing portion thereof, the nozzles 70 are suppliedwith cleaning liquid.

Furthermore, the surface cleaning machine 10 may comprise a suctiondevice 80 via which excess liquid is capable of being sucked up from thefloor/ground 18. The suction device 80 comprises for example a suctionbar 82 which is in contact with the floor/ground 18 when operating incleaning mode. Liquid is sucked up via said suction bar 82 and receivedin a tank 84. The tank 84 is a dirty water tank.

By way of example, the suction bar 82 is arranged rearward of the rearwheel device 16 relative to a forward travel direction.

In operation of the surface cleaning machine 10 in which steering on thefront wheel device 14 is effected in the dry area of the floor/ground 18and control of the rear wheel device 16 is effected in the wet area ofthe floor/ground 18, the first electromotive drive device 46 and thesecond electromotive drive device 48 are differentially controlleddepending on the detected steering angle at the front wheel device 14.Improved traction can thereby be achieved. In particular when travellingon slippery surfaces, breakaway in cornering can be prevented bycorresponding control action. Via the first electromotive drive device46 and the second electromotive drive device 48, the left rear wheel 38and the right rear wheel 40 can be braked individually and independentlyof each other, or different rotational speeds can be adjusted.

The improved traction, in particular on slippery surfaces, is improvedby sensing corresponding wheel parameters by the sensor device 58.

Relatively high cornering speeds can thereby be achieved, adapted to theconditions encountered.

It is preferred that an additional brake device be provided which isformed by way of a frictional cone for example, in order to achieve ahigh braking effect.

The solution in accordance with the invention allows the optimal speedto be achieved, depending on the ground conditions encountered; cleaningliquid, in particular one containing soft soap, can make thefloor/ground 18 slippery. The solution in accordance with the inventionensures that steering guidance by the front wheel device 14 is effectedin the “dry area”, i.e., forward of the application area 68.

A second exemplary embodiment of a surface cleaning machine constructedin accordance with the invention, shown schematically in FIG. 3 andindicated therein at 86, is a sweeping machine. Said sweeping machinecomprises one or more sweeping heads 88. This sweeping machine 86 in itsbasic configuration is described for example in DE 10 2004 022 359 A1,which is incorporated herein and made a part hereof by reference in itsentirety and for all purposes.

The surface cleaning machine 86 comprises a front wheel device 14 and arear wheel device 16 corresponding to those of the surface cleaningmachine 10, wherein the rear wheel device 16 in turn comprises separateelectromotive drive devices 46, 48 for a left rear wheel 38 and a rightrear wheel 40.

The surface cleaning machine 86 is provided with a control device 50corresponding to the control device 50 on the surface cleaning machine10; like reference designations indicate like elements.

By way of the control device 50, the left rear wheel 38 and the rightrear wheel 40 of the surface cleaning machine 86 are controlledindividually depending on a steering angle at the front wheel device 14.

In the surface cleaning machine 86, no application device 66 is providedbetween the front wheel device 14 and the rear wheel device 16.

Improved traction on “slippery” grounds, particularly in cornering anduphill driving, can also be achieved with the sweeping machine 86. Forexample, when the surface cleaning machine 86 runs on wet leaves,enhanced driving safety can be provided by controlling the left rearwheel 38 and the right rear wheel 40 individually depending on thesteering angle position.

The surface cleaning machine 86 may also be configured for example as ascrubbing machine in which an application device is provided, whereinthe application area (relative to a forward travel direction) ispositioned in front of the front wheel device 14 or behind the rearwheel device 16.

LIST OF REFERENCE CHARACTERS

-   10 surface cleaning machine-   12 body-   14 front wheel device-   16 rear wheel device-   18 floor/ground-   20 steering roller-   22 steering device-   24 angular position-   26 central axis-   27 straight ahead travelling direction-   28 steering axis-   30 seat-   32 steering wheel-   34 steering angle sensor device-   36 axis of rotation-   38 left rear wheel-   40 right rear wheel-   42 a shaft-   42 b shaft-   44 axes of rotation-   46 first electromotive drive device-   48 second electromotive drive device-   50 control device-   52 actuating pedals-   54 operative connection for signal communication-   56 a operative connection for signal communication-   56 b operative connection for signal communication-   58 sensor device-   60 a first part-   60 b second part-   62 scrubbing element-   64 underside-   66 application device-   68 application area-   70 nozzle-   72 differential device-   74 anti-slip control-   76 speed limiting device-   78 tank-   80 suction device-   82 suction bar-   84 tank-   86 surface cleaning machine-   88 sweeping head

1. A self-propelled surface cleaning machine, comprising: a front wheeldevice; a steering device associated with the front wheel device; asteering angle sensor device by which a steering angle at the frontwheel device is detectable; a rear wheel device having at least one leftrear wheel and at least one right rear wheel; a first electromotivedrive device associated with the at least one left rear wheel; a secondelectromotive drive device associated with the at least one right rearwheel; a cleaning liquid application device by which cleaning liquid isapplicable to a floor/ground in an application area that is arrangedbetween the front wheel device and the rear wheel device; and a controldevice operatively connected for signal communication with the steeringangle sensor device, the first electromotive drive device and the secondelectromotive drive device, wherein each of the first electromotivedrive device and the second electromotive drive device is controllableindividually depending on signals from the steering angle sensor device.2. The self-propelled surface cleaning machine in accordance with claim1, wherein the control device comprises an electronic differentialdevice for the at least left rear wheel and the at least one right rearwheel.
 3. The self-propelled surface cleaning machine in accordance withclaim 1, wherein the front wheel device comprises one or more steeringrollers.
 4. The self-propelled surface cleaning machine in accordancewith claim 1, wherein the control device comprises a speed limitingdevice, wherein a maximum speed is dependent on the steering angle. 5.The self-propelled surface cleaning machine in accordance with claim 1,wherein control parameters of the control device for the firstelectromotive drive device and the second electromotive drive devicecomprise rotational speed and direction of rotation.
 6. Theself-propelled surface cleaning machine in accordance with claim 1,wherein the rear wheel device has a sensor device associated with it,said sensor device sensing wheel parameters, and wherein the sensordevice is operatively connected for signal communication with thecontrol device.
 7. The self-propelled surface cleaning machine inaccordance with claim 6, wherein the control device comprises ananti-slip control.
 8. The self-propelled surface cleaning machine inaccordance with claim 1, wherein one or more nozzles for cleaning liquidare provided, said nozzles being arranged between the front wheel deviceand the rear wheel device.
 9. The self-propelled surface cleaningmachine in accordance with claim 1, wherein in forward travel, applyingcleaning liquid to the floor/ground is behind the front wheel device andin front of the rear wheel device.
 10. The self-propelled surfacecleaning machine in accordance with claim 1, wherein one or morescrubbing elements are provided.
 11. The self-propelled surface cleaningmachine in accordance with claim 1, wherein said self-propelled surfacecleaning machine is configured as a scrubbing machine.
 12. Theself-propelled surface cleaning machine in accordance with claim 1,wherein said self-propelled surface cleaning machine isattendant-controlled.
 13. A self-propelled surface cleaning machine,comprising: a front wheel device; a steering device associated with thefront wheel device; a steering angle sensor device by which a steeringangle at the front wheel device is detectable; a rear wheel devicehaving at least one left rear wheel and at least one right rear wheel; afirst electromotive drive device associated with the at least one leftrear wheel; a second electromotive drive device associated with the atleast one right rear wheel; and a control device operatively connectedfor signal communication with the steering angle sensor device, thefirst electromotive drive device and the second electromotive drivedevice, wherein each of the first electromotive drive device and thesecond electromotive drive device are controllable individuallydepending on signals from the steering angle sensor device.
 14. Theself-propelled surface cleaning machine in accordance with claim 13,wherein the cleaning machine is a sweeping machine.
 15. A method foroperating a self-propelled surface cleaning machine, said cleaningmachine having a steered front wheel device and a driven rear wheeldevice; comprising: applying a cleaning liquid to a floor/ground to becleaned, with an application area being located between the front wheeldevice and the rear wheel device; and controlling individually a firstdrive device associated with a left rear wheel and a second drive deviceassociated with a right rear wheel, depending on a steering angle at thefront wheel device.
 16. The method in accordance with claim 15, whereinthe rear wheel device is electromotively driven, with an electronicdifferential device being used for the first drive device and the seconddrive device.
 17. The method in accordance with claim 15, wherein thefirst drive device and the second drive device are controlled in respectof rotational speed and direction of rotation.
 18. The method inaccordance with claim 17, wherein a maximum speed is predetermined, saidmaximum speed depending on the steering angle.
 19. A method foroperating a self-propelled surface cleaning machine, said cleaningmachine having a steered front wheel device and a driven rear wheeldevice; comprising: controlling individually a first drive deviceassociated with a left rear wheel and a second drive device associatedwith a right rear wheel, depending on a steering angle at the frontwheel device.
 20. The method in accordance with claim 19, wherein thecleaning machine is a sweeping machine.